Yes, Metaball is a good tool. You can make nice cartoon looks-like clouds, as I used here:

http://i232.photobucket.com/albums/ee104/noviski/Carrara/cena_urso07.jpg

With a glow channel and some blur the results are decent, IMHO. ;)

(Edited: And the tree foliage, the honey drips are Metaballs too.)